Light guides are employed for a range of functions including illumination, backlighting, signage and display purposes. Light guides may be constructed in a number of different ways including from an injection molded or machined transparent plastic component, such as poly(methyl methacrylate (PMMA), wherein a light source, such as a fluorescent lamp or a light emitting diode, is integrated, such as with a mechanical attachment. Light emitted from the light source is guided through the light guide by internal reflection. In various examples, the internal reflection is total internal reflection.
The better the coupling of the light source and the light guide, generally the better more efficient the transmittance of light from the light source to an opposing end of the light guide. In some applications, the light is emitted into the plane of the light guide to increase performance. In other applications, the length of the light guide is minimized to increase performance. However, minimizing the length of the light guide can also compromise light uniformity, e.g. by creation of dark spots and/or more intense areas of light near the light source.
In addition to producing light, light sources also produce heat. For this reason, many light guides are designed to be resistant to heat. However, in so doing, such light guides are sometimes bulky and heavy, thereby increasing production and manufacturing costs. In addition, the bulk of the light guides can adversely affect optical properties. Moreover, PMMA tends to physically degrade after heating/ageing. Accordingly, there is an opportunity to develop an improved light guide.